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The Logic of Typed Feature Structures
, 1992
"... Feature Structures and Path Congruences. The discussion of abstract feature structures raises a historical difficulty. While I do not dispute that the full theoretical investigation of feature structures modulo renaming is correctly attributed to Moshier, the idea of representing renaming classes b ..."
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Cited by 330 (3 self)
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Feature Structures and Path Congruences. The discussion of abstract feature structures raises a historical difficulty. While I do not dispute that the full theoretical investigation of feature structures modulo renaming is correctly attributed to Moshier, the idea of representing renaming classes by equivalence relations over paths seems an obvious variant of the representation of such classes as deductively closed sets of path equations in Pereira and Shieber's account (1984) of the semantics of PATRII, which is further explored in Shieber's dissertation (1989).
A Logical Semantics for Feature Structures
, 1986
"... Unificationbased grammar formalisms use structures containing sets of features to describe linguistic objects. Although computational algo rithms for unification of feature structures have been worked out in experimental research, these algorithms become quite complicated, and a more precise descr ..."
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Cited by 127 (4 self)
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Unificationbased grammar formalisms use structures containing sets of features to describe linguistic objects. Although computational algo rithms for unification of feature structures have been worked out in experimental research, these algorithms become quite complicated, and a more precise description of feature structures is desirable. We have developed a model in which descriptions of feature structures can be regarded as logical formulas, and interpreted by sets of directed graphs which satisfy them. These graphs are, in fact, transition graphs for a special type of deterministic finite automaton.
Parsing Strategies with 'Lexicalized' Grammars: Application to Tree Adjoining Grammars
 IN PROCEEDINGS OF THE 12 TH INTERNATIONAL CONFERENCE ON COMPUTATIONAL LINGUISTICS (COLING'88
, 1988
"... In this paper we present a general parsing strategy that arose from the development of an Earicytype parsing algorithm for TAGs (Schabes and Joshi 1988) and from recent linguistic work in TAGs (Abeille 1988). In our approach ..."
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Cited by 115 (16 self)
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In this paper we present a general parsing strategy that arose from the development of an Earicytype parsing algorithm for TAGs (Schabes and Joshi 1988) and from recent linguistic work in TAGs (Abeille 1988). In our approach
Unification: A multidisciplinary survey
 ACM Computing Surveys
, 1989
"... The unification problem and several variants are presented. Various algorithms and data structures are discussed. Research on unification arising in several areas of computer science is surveyed, these areas include theorem proving, logic programming, and natural language processing. Sections of the ..."
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Cited by 103 (0 self)
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The unification problem and several variants are presented. Various algorithms and data structures are discussed. Research on unification arising in several areas of computer science is surveyed, these areas include theorem proving, logic programming, and natural language processing. Sections of the paper include examples that highlight particular uses
Using Restriction to Extend Parsing Algorithms for ComplexFeatureBased Formalisms
 In 23th Annual Meeting of the Association for Computational Linguistics
, 1985
"... Grammar formalisms based on the encoding of grammatical information in complexvalued feature systems enjoy some currency both in linguistics and naturallanguageprocessing research. Such formalisms can be thought of by analogy to ..."
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Cited by 84 (3 self)
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Grammar formalisms based on the encoding of grammatical information in complexvalued feature systems enjoy some currency both in linguistics and naturallanguageprocessing research. Such formalisms can be thought of by analogy to
Feature Constraint Logics for Unification Grammars
 Journal of Logic Programming
, 1992
"... This paper studies feature description languages that have been developed for use in unification grammars, logic programming and knowledge representation. The distinctive notational primitive of these languages are features that can be understood as unary partial functions on a domain of abstract ..."
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Cited by 83 (10 self)
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This paper studies feature description languages that have been developed for use in unification grammars, logic programming and knowledge representation. The distinctive notational primitive of these languages are features that can be understood as unary partial functions on a domain of abstract objects. We show that feature description languages can be captured naturally as sublanguages of firstorder predicate logic with equality and show the equivalence of a loose Tarski semantics with a fixed feature graph semantics for quantifierfree constraints. For quantifierfree constraints we give a constraint solving method and show the NPcompleteness of satisfiability checking. For general feature constraints with quantifiers satisfiability is shown to be undecidable. Moreover, we investigate an extension of the logic with sort predicates and setdenoting expressions called feature terms.
Subcategorization Acquisition
, 2002
"... Manual development of large subcategorised lexicons has proved difficult because predicates change behaviour between sublanguages, domains and over time. Yet access to a comprehensive subcategorization lexicon is vital for successful parsing capable of recovering predicateargument relations, and pr ..."
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Cited by 72 (13 self)
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Manual development of large subcategorised lexicons has proved difficult because predicates change behaviour between sublanguages, domains and over time. Yet access to a comprehensive subcategorization lexicon is vital for successful parsing capable of recovering predicateargument relations, and probabilistic parsers would greatly benefit from accurate information concerning the relative likelihood of different subcategorisation frames (scfs) of a given predicate. Acquisition of subcategorization lexicons from textual corpora has recently become increasingly popular. Although this work has met with some success, resulting lexicons indicate a need for greater accuracy. One significant source of error lies in the statistical filtering used for hypothesis selection, i.e. for removing noise from automatically acquired scfs. This thesis builds on earlier work in verbal subcategorization acquisition, taking as a starting point the problem with statistical filtering. Our investigation shows that statistical filters tend to work poorly because not only is the underlying distribution zipfian, but there is also very little correlation between conditional distribution of
An Efficient AugmentedContextFree Parsing Algorithm
 Computational Linguistics
, 1987
"... This paper introduces an efficient online parsing algorithm, and focuses on its practical application to natural language interfaces. The algorithm can be viewed as a generalized LR parsing algorithm that can handle arbitrary contextfree grammars, including ambiguous grammars. Section 2 describes ..."
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Cited by 70 (3 self)
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This paper introduces an efficient online parsing algorithm, and focuses on its practical application to natural language interfaces. The algorithm can be viewed as a generalized LR parsing algorithm that can handle arbitrary contextfree grammars, including ambiguous grammars. Section 2 describes the algorithm by .extending the standard LR parsing algorithm with the idea of a "graphstructured stack". Section 3 describes how to represent parse trees efficiently, so that all possible parse trees (the parse forest) take at most polynomial space as the ambiguity of a sentence grows exponentially. In section 4, several examples are given. Section 5 presents several empirical results of the algorithm's practical performance, including comparison with Earley's algorithm. In section 6, we discuss how to enhance the algorithm to handle augmented contextfree grammars rather than pure contextfree grammars. Section 7 describes the concept of online parsing, taking advantage of lefttoright operation of our parsing algorithm. The online parser parses a sentence strictly from left to right, and starts parsing as soon as the user types in the first word, without waiting for the end of line. Benefits of online parsing are then discussed. Finally, several versions of online parser have been implemented, and they are mentioned in section 8
Some ChartBased Techniques For Parsing IllFormed Input
, 1989
"... We argue f the usefulness of an active chart as the bas of a system that searches for th globally most plausible explanation of failur to syntactically parse a given input. We suggest semanticsfree, grammarindependent techniques for parsing inputs displaying simple kinds of RIformedness and discus ..."
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Cited by 55 (0 self)
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We argue f the usefulness of an active chart as the bas of a system that searches for th globally most plausible explanation of failur to syntactically parse a given input. We suggest semanticsfree, grammarindependent techniques for parsing inputs displaying simple kinds of RIformedness and discuss the search issues involved.
Practical Unificationbased Parsing of Natural Language
, 1993
"... The thesis describes novel techniques and algorithms for the practical parsing of realistic Natural Language (NL) texts with a widecoverage unificationbased grammar of English. The thesis tackles two of the major problems in this area: firstly, the fact that parsing realistic inputs with such gr ..."
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Cited by 49 (7 self)
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The thesis describes novel techniques and algorithms for the practical parsing of realistic Natural Language (NL) texts with a widecoverage unificationbased grammar of English. The thesis tackles two of the major problems in this area: firstly, the fact that parsing realistic inputs with such grammars can be computationally very expensive, and secondly, the observation that many analyses are often assigned to an input, only one of which usually forms the basis of the correct interpretation. The thesis starts by presenting a new unification algorithm, justifies why it is wellsuited to practical NL parsing, and describes a bottomup active chart parser which employs this unification algorithm together with several other novel processing and optimisation techniques. Empirical results demonstrate that an implementation of this parser has significantly better practical